code: def find_on_path(self, exename, path_directories=None):
      if not path_directories:
          path_directories = os.environ["PATH"].split(os.pathsep)
      for dir_name in path_directories:
          fullpath = os.path.join(dir_name, exename)
          if os.path.isfile(fullpath):
              return fullpath
      return None
  
imports: import os
  import sys
  import re
  import subprocess
  from setuptools import setup, Extension
  from distutils.command.build_ext import build_ext
  from distutils.ccompiler import get_default_compiler
  from distutils.errors import CompileError
  import configparser
label_desc: Use image node_id 3 for calling the PostgresConfig obj's underlying member method code with example usage: obj.find_on_path(exename, path_directories) and returns: None, fullpath